1. Field of the Invention
This invention relates to a power supply device of a camera which uses first and second source batteries to effect power supply to discrete power-supplied portions.
2. Description of the Prior Art
Some of the power supply devices of cameras are designed such that portions to which the power supply and the non-power supply are frequently changed over (for example, a film feeding device, an automatic exposure device and a flash device) is supplied with an electric power by the first power source battery and portions to which the power supply is hardly cut off (for example, a memory IC for counter which stores the number of photographed frames and an IC for controlling said devices) is supplied with an electric power by the second power source battery. In the power supply device of this type, battery lids are provided discretely and therefore, it has sometimes happened that the battery lid for the first power source battery and the battery lid for the second power source battery are opened by mistake.
If the battery lid for the second power source battery is opened by mistake when the battery lid for the first power source battery should be opened, power supply will be effected from the first power source battery but not from the second power source battery and an unexpected electric current or electrical signal will flow and each IC may cause unexpected malfunctioning (for example, the counter function may be all cleared) or may be destroyed. Thus, in some power supply devices, it is not desirable to cut off only the power supply from the second power source battery or cut off the power supply from the second power source battery prior to cutting off the power supply from the first power source battery.